This invention relates to a semiconductor laser device which may be contained in a compact disc player or an optical pickup.
FIG. 4 shows the circuit structure of a prior art semiconductor laser device of this kind with a laser diode 1 contained inside a package 10, connected through wires or lead lines to its terminals T.sub.1 and T.sub.2 outside for applying a voltage thereacross and thereby providing an optical output according to the applied input voltage.
While there is no source voltage being applied to such a circuit, it sometimes happens that the static electricity of the circuit causes a current (referred to as "a surge current") to flow through, thereby degrading or destroying the diode because laser diodes are typically much more fragile than ordinary ICs against a surge current.
Since prior art semiconductor laser devices are structured such that the surge current would completely flow into the laser diode, the laser diode is easily degraded or destroyed. In other words, prior art semiconductor laser devices had only a very low resistance against surge currents.
It was necessary therefore to take an adequate measure when a prior art semiconductor laser device was installed in its driving circuit, for example, in order to prevent such degradation or destruction of the laser diode by a surge current. If a circuit for absorbing the surge current is to be attached externally, however, this will increase the total area of the set into which the semiconductor laser device is incorporated.